Participatory mapping identifies risk areas and environmental predictors of endemic anthrax in rural Africa (original) (raw)
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Scientific Reports
Using data collected from previous (n = 86) and prospective (n = 132) anthrax outbreaks, we enhanced prior ecological niche models (ENM) and added kernel density estimation (KDE) approaches to identify anthrax hotspots in Kenya. Local indicators of spatial autocorrelation (LISA) identified clusters of administrative wards with a relatively high or low anthrax reporting rate to determine areas of greatest outbreak intensity. Subsequently, we modeled the impact of vaccinating livestock in the identified hotspots as a national control measure. Anthrax suitable areas included high agriculture zones concentrated in the western, southwestern and central highland regions, consisting of 1043 of 1450 administrative wards, covering 18.5% country landmass, and hosting 30% of the approximately 13 million cattle population in the country. Of these, 79 wards covering 5.5% landmass and hosting 9% of the cattle population fell in identified anthrax hotspots. The rest of the 407 administrative wards...
2021
Background Developing disease risk maps for priority endemic and episodic diseases is becoming increasingly important for more effective disease management, particularly in resource limited countries. For endemic and easily diagnosed diseases such as anthrax, using historical data to identify hotspots and start to define ecological risk factors of its occurrence is a plausible approach. Using 666 livestock anthrax events reported in Kenya over 60 years (1957–2017), we determined the temporal and spatial patterns of the disease as a step towards identifying and characterizing anthrax hotspots in the region. Methods Data were initially aggregated by administrative unit and later analyzed by agro-ecological zones (AEZ) to reveal anthrax spatio-temporal trends and patterns. Variations in the occurrence of anthrax events were estimated by fitting Poisson generalized linear mixed-effects models to the data with AEZs and calendar months as fixed effects and sub-counties as random effects. ...
Scientific Reports
Anthrax is caused by, Bacillus anthracis, a soil-borne bacterium that infects grazing animals. Kenya reported a sharp increase in livestock anthrax cases from 2005, with only 12% of the sub-counties (decentralised administrative units used by Kenyan county governments to facilitate service provision) accounting for almost a third of the livestock cases. Recent studies of the spatial extent of B. anthracis suitability across Kenya have used approaches that cannot capture the underlying spatial and temporal dependencies in the surveillance data. To address these limitations, we apply the first Bayesian approach using R-INLA to analyse a long-term dataset of livestock anthrax case data, collected from 2006 to 2020 in Kenya. We develop a spatial and a spatiotemporal model to investigate the distribution and socio-economic drivers of anthrax occurrence and incidence at the national and sub-county level. The spatial model was robust to geographically based cross validation and had a sensi...
Modeling the spatial distribution of anthrax in southern Kenya
PLOS Neglected Tropical Diseases, 2021
Background Anthrax is an important zoonotic disease in Kenya associated with high animal and public health burden and widespread socio-economic impacts. The disease occurs in sporadic outbreaks that involve livestock, wildlife, and humans, but knowledge on factors that affect the geographic distribution of these outbreaks is limited, challenging public health intervention planning. Methods Anthrax surveillance data reported in southern Kenya from 2011 to 2017 were modeled using a boosted regression trees (BRT) framework. An ensemble of 100 BRT experiments was developed using a variable set of 18 environmental covariates and 69 unique anthrax locations. Model performance was evaluated using AUC (area under the curve) ROC (receiver operating characteristics) curves. Results Cattle density, rainfall of wettest month, soil clay content, soil pH, soil organic carbon, length of longest dry season, vegetation index, temperature seasonality, in order, were identified as key variables for pr...
Sporadic anthrax outbreaks have occurred in and around Uganda's Queen Elizabeth National Park (QENP) for years, affecting wildlife, domestic animals, and humans. Reported outbreaks (2004e2005 and 2010) in QENP collectively killed over 500 wild animals and over 400 domestic animals. A 2011 outbreak in Sheema district temporarily froze local markets while killing two humans and seven bovines. One Health is multidisciplinary at its core, yet studies sometimes focus on the effects of animals on human health to the detriment of investigating the surrounding ecological and cultural contexts. Participatory methods connect problems e such as disease e to their context. A multidisciplinary team used participatory epidemiology and conventional structured questionnaires to investigate the impacts of anthrax on human livelihoods and the related perceptions of conservation, public health, and veterinary health efforts in the QENP area. Proximities to previous anthrax outbreaks and to QENP were treated as risk factors in the collection and evaluation of data. Participants' feedback indicates that anthrax prevalence may be greater than officially reported. Community member perceptions about anthrax and other diseases appear to be more closely related to their proximity to QENP than their proximity to anthrax outbreaks. Neither risk factor had a strong effect on knowledge of disease, nor any effect on behaviors associated with disease response or control. Instead, participants reported that social pressures, the economics of poverty, and the lack of health and veterinary infrastructure highly influenced responses to disease. The complex connections between the social needs and the economic context of these communities seem to be undermining current anthrax control and education measures. This livelihood-based decision-making may be unlikely to respond to educational intervention alone. This study provides a strong base for further research and for improvements in effective disease control.
Predictability of anthrax infection in the Serengeti, Tanzania
The Journal of applied ecology, 2011
Anthrax is endemic throughout Africa, causing considerable livestock and wildlife losses and severe, sometimes fatal, infection in humans. Predicting the risk of infection is therefore important for public health, wildlife conservation and livestock economies. However, because of the intermittent and variable nature of anthrax outbreaks, associated environmental and climatic conditions, and diversity of species affected, the ecology of this multihost pathogen is poorly understood.We explored records of anthrax from the Serengeti ecosystem in north-west Tanzania where the disease has been documented in humans, domestic animals and a range of wildlife. Using spatial and temporal case-detection and seroprevalence data from wild and domestic animals, we investigated spatial, environmental, climatic and species-specific associations in exposure and disease.Anthrax was detected annually in numerous species, but large outbreaks were spatially localized, mostly affecting a few focal herbivo...